package cn.luyifushi.utils;

import cn.luyifushi.sys.entity.User;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.security.Keys;
import lombok.Data;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.stereotype.Component;

import javax.crypto.SecretKey;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

/**
 * @author sword-l
 * @version 1.0.0
 * @title token工具类
 * @description
 **/
@Data
@ConfigurationProperties(prefix = "jwt")
@Component
public class JwtUtils {
    //密钥
    private String secret;
    // 过期时间 毫秒
    private Long expiration;

    /**
     * 从数据声明生成令牌
     * @param claims 数据声明
     * @return 令牌
     */
    private String generateToken(Map<String, Object> claims) {
        Date expirationDate = new Date(System.currentTimeMillis() + expiration);
        JwtBuilder jwtBuilder = Jwts.builder();
        for (Map.Entry<String, Object> entry : claims.entrySet()) {
            jwtBuilder.claim(entry.getKey(), entry.getValue());
        }
        // 设置过期时间和签名，并生成JWT
        return jwtBuilder
                .setExpiration(expirationDate)
                .signWith(SignatureAlgorithm.HS512, secret)
                .compact();
    }

    /**
     * 从令牌中获取数据声明
     *
     * @param token 令牌
     * @return 数据声明
     */
    public Claims getClaimsFromToken(String token) {
        Claims claims;
        try {
            claims = Jwts.parser().setSigningKey(secret).build().parseClaimsJws(token).getBody();
        } catch (Exception e) {
            claims = null;
        }
        return claims;
    }

    /**
     * 生成令牌
     * @param userDetails 用户
     * @return 令牌
     */
    public String generateToken(UserDetails userDetails) {
        Map<String, Object> claims = new HashMap<>(2);
        claims.put(Claims.SUBJECT, userDetails.getUsername());
        claims.put(Claims.ISSUED_AT, new Date());
        return generateToken(claims);
    }

    /**
     * 从令牌中获取用户名
     *
     * @param token 令牌
     * @return 用户名
     */
    public String getUsernameFromToken(String token) {
        String username;
        try {
            Claims claims = getClaimsFromToken(token);
            username = claims.getSubject();
        } catch (Exception e) {
            username = null;
        }
        return username;
    }
   /**
    * 判断令牌是否过期
    * @param token 令牌
    * @return 是否过期
    */
    public Boolean isTokenExpired(String token) {
        Claims claims = getClaimsFromToken(token);
        Date expiration = claims.getExpiration();
        return expiration.before(new Date());
    }

    /**
     * 刷新令牌
     *
     * @param token 原令牌
     * @return 新令牌
     */
    public String refreshToken(String token) {
        String refreshedToken;
        try {
            Claims claims = getClaimsFromToken(token);
            // 创建一个新的Map，并复制旧的声明信息
            Map<String, Object> newClaimsMap = new HashMap<>(claims);
            // 设置新的签发时间
            newClaimsMap.put(Claims.ISSUED_AT, new Date());
            refreshedToken = generateToken(newClaimsMap);
        } catch (Exception e) {
            refreshedToken = null;
        }
        return refreshedToken;
    }

    /**
     * 验证令牌
     *
     * @param token 令牌
     * @param userDetails 用户
     * @return 是否有效
     */
    public Boolean validateToken(String token, UserDetails userDetails) {
        User user = (User) userDetails;
        String username = getUsernameFromToken(token);
        return (username.equals(user.getUsername()) && !isTokenExpired(token));
    }
}
